I. Field of the Invention
This invention relates generally to methods for removing pollutants from stormwater runoff, and more particularly to the design of an underground containment vessel designed to remove solids and targeted dissolved chemical elements that may be present in stormwater runoff.
II. Discussion of the Prior Art
Stormwater runoff from building roofs, parking lots, roadways, etc. picks up contaminants that can be harmful to the environment if allowed to pass, untreated, into rivers, streams, aquifers and the like. The EPA has data suggesting that polluted stormwater runoff is a leading cause of impairment to the nearly 40% of surveyed U.S. water bodies which do not meet water quality standards. Over land or via storm sewer systems, polluted runoff is discharged, often untreated, directly into local water bodies. The pollutants may include solids including sand, gravel, grass, leaves, and the like. It is also known that stormwater runoff can pick up various nutrients, including phosphorous, potassium, and nitrates from lawn and agricultural fertilizers and heavy metals, including cadmium, zinc, copper, lead, nickel, chromium from metal building roofs, gutters, downspouts and the like. Stormwater runoff from roadways and parking lots include polysiclic, aromatic hydrocarbons from oils and motor fuels. Of course, significant concentrations of solids and dissolved pollutants should not be discharged to ground water or open watercourses. Also, the introduction of this water into the city sewer system is not desired, since a corresponding capacity must be reserved in this sewer treatment facility for this purpose. The invention is concerned with the problem of purifying such water, especially heavy-metal ion containing wastewater from metal roofs, such as copper roofs, prior to its seeping into the ground or prior to its introduction into a body of water.
It is accordingly a principle object of the present invention to provide a structurally simple filter element for water loaded with solid particles and dissolved toxic substances as well as a purification system suitable for said filter, which system effectively removes the solid particles and particulate toxic substances from the water without great expense.